Apparatus for heating and cooling air



Feb. 25, 1964 H. J. SCHARRES APPARATUS FOR HEATING AND COOLING AIR Filed June 14, 1960 INVENTOR HARRY J. Sumnmzs 1:5//%, W, 70

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United States Patent 3,122,2e2 Al PARATUS FOR HEATING AND COOLDQG AER Harry J. charres, Qlarendon Hills, 111. Filed .lune 14, 1960, Ser. N 36, 76 Clairns. (Cl. 165-35) The invention relates to an improved apparatus for conditioning the air supply for rooms or other enclosed spaces.

One object of the invention is to provide air conditioning which utilizes relatively inexpensive cooling and heating equipment and which permits both to be operated at the most efficient and economical levels, thus reducing operating costs to a minimum.

A more specific object is to provide air conditioning in which a cooled stream of air is passed through a heater and recombined with the unheated air and in which the ratios of the heated to unheated air is regulated by variably throttling the flow of heated and unheated air without substantially reducing the total volume of air flow.

Another object is to provide apparatus for carrying out the improved air conditioning method in an eiiicient and economical manner. More specifically, it is an o ject of the invention to provide air conditioning apparatus embodying means for moving a predetermined volume of air through a cooler and thereafter directing the cooled air along two separate paths, one of which includes a heater and then recombining and mixing the air streams, characterized by the provision of damper means located downstream from the heater for complementally varying the volume of air movin along each path without substantially changing the total volume of air flow.

Still another object is to provide air conditioning apparatus including a mixing chamber having a damper controlled cold air inlet and a damper controlled hot air inlet in which the dampers are linked together for complemental opening and closing movements such that their combined effective areas remain substantially constant for all positions of the dampers. A more specific object is to provide a damper arrangement of the type referred to in which the efiective areas of the respective dampers are so related that the cold air damper alone is capable of accommodating the entire volume of air when fully opened.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawings in which:

FIGURE 1 is a partially diagrammatic, partially sectioned view of air conditioning apparatus embodying the features of the invention.

FIG. 2 is a side view of the damper mechanism and the operating linkage forming a part of the apparatus, the dampers being shown in one extreme position of adjustment.

FIG. 3 is a view similar to FIG. 2 but showing the dampers in the other extreme position of adjustment.

FIG. 4 is a somewhat enlarged diagrammatic view of the linkage coupling the dampers for simultaneous operation.

Although the invention has been shown and will be described in some detail with reference to a particular embodiment, there is no intention to limit it to such detail. On the contrary, it is intended herein to cover all alternatives, modifications and adaptations falling within the spirit and scope of the invention as defined by the appended claims.

For purposes of illustration, the invention has been disclosed in a form suitable for conditioning the air supply of a room or a series of rooms to maintain it in a 3,1222%? Patented Feh. 25, 194

condition for comfortable human occupancy. Such an environment imposes definite limits with respect to temperature and humidity. It will be appreciated, of course, that the invention may be used for tempering or conditioning the air supply for spaces utilized for other purposes and that under such conditions different temperature and humidity conditions may be required.

In conditioning the air supply of a room in accordance with my improved method, provision is made for the forced delivery of conditioned air to the room at a constant volumetric rate. Before discharge into the space, the air is brought to a predetermined temperature and humidity level by subjecting it to a conditioning process involving both cooling and heating applied in a novel manner which afiords substantial economies in operation as compared with conventional air conditioning procedures. More particularly, in accordance with the invention the entire stream of moving air is cooled to a moderate temperature somewhat below the desired final temperature required. After cooling the air stream is divided and a predetermined portion is diverted through a heater maintained at a constant relatively high temperature. Thereafter the hot and cold air streams are recombined and thoroughly mixed before discharge into the room or space to be conditioned.

Further, in accordance with the invention, the final air temperature-that is, the temperature of the air as supplied to the room is regulated by varying the ratio of the air diverted through the heater with respect to that by-passed by the heater. An important consideration in this connection is that the variation is effected in a manner such that the total volume of air flow remains substantially constant regardless of any changes in the ratio.

This mode of temperature control permits operation of the system at the most economical level, taking into consideration the practical limitations involved in the heating and cooling process. Thus, in general, cooling air to a moderately low temperature can be effected by simple, inexpensive refrigerating equipment which can be operated at relatively low cost. By moderately low temperature is meant temperatures Within the range of from 30 F. to 60 F. Also, when the air is to be supplied to space intended for human occupancy, humidity requirements make it undesirable to reduce the temperature below that level. In practice, the most economical minimum temperature to be used is that which reduces the moisture content of the treated air to a desired level.

On the other hand, air can be easily and economically heated to temperatures as high as 200 F. Moreover, with the type of temperature regulation contemplated by the invention, only a comparatively small proportion of the total volume of circulating air will require heating. It has been found that under average conditions, most satisfactory and economical results are obtained when the ratio between the volumes of heated and unheated air is on the rder of 1:2. More specifically, optimum results are obtained when the volume of air diverted through the heater does not exceed of the total volun e of air.

it will be appreciated, of course, that in certain types of air conditioning installations or under some extreme conditions, it may be necessary to depart from the above ratio. However, it is believed that the advantages afiorded by the invention may be realized when the ratios are Within the range of from 20% to and, accordingly, those ratios are asserted as the limits of the present invention.

While the improved method of air conditioning may he carried out with various types of commercially avail able apparatus, particularly efficient operation is possible with apparatus constructed and arranged as shown in 3 FEGS. 14 of drawings. The exemplary apparatus includes a fan or blower 1% for moving the air to be conditioned. As shown, the blower is arranged to draw air through inlet 11 and discharge it into a chamber 12. The air may be drawn entirely from the space to be conditioned or from outside or from both sources simultaneously in any desired proportions. Theblower may be of any conventional construction and may be driven by any preferred type ofprime mover such as an electric motor.

The chamber 12 defined by walls 13 is a cooling chamber and to this end is equipped with a cooling coil 14. Cold brine or other cooling medium is circulated through the coil by refrigerating apparatus indicated at 15 which may be of any preferred character. If desired, the chamber 12 may also be equipped with means for adding moisture to the air passing through the chamber, such means being located ahead of the cooling coil so that the latter may etle-ctively control the total moisture content or" the air as discharged from the cooling chamber.

In the exemplary apparatus the chamber 12 is connected by a duct 16 with a somewhat larger chamber 17 which in turn opens into a mixing chamber 18. The chamber 17 is defined by Walls 19 and is divided by a partition 2% to form two parallel passageways 21 and 22 opening to the mixing chamber. One of the passageways, in this instance, the passageway 21, is equipped with a heater 23 which may be of any preferred character but for convenience has been shown as a coil through which a heating medium is circulated by a heating device 24.

In accordance with the invention, air flow through the passageway 21 and 22 is controlled by dampermechanism of a novel character operative to proportion the flow through the passages without substantially altering the total volume of airpassing through the system.

The damper mechanism includes two separate dampers 25 and 26 respectively adjustable to eiiect the flow of hot and cold air in the proportions required to bring the two air streams when mixed to a predetermined desired temperature. In accordance with the invention, the damper 25 for the hot air passage is constructed to present a maximum effective area substantially smaller than the effective area of the cold air damper 26. While the ratio between damper areas may vary according to particular system requirements, for best over-all elhciency in a room air conditioner, the hot air damper is constructed to provide a maximum effective. area approximately onehalf of the maximum effective area of the cold air damper.

The dampers 25 and 26 may be structurally alike except for size. Thus, the damper 25 as shown comprises a generally rectangular frame 27 having suitable bearings at opposite sides for journalling the pivot shafts 28 of a plurality of vanes or damper blades 29. In the particular embodiment illustrated two of the blades 29 are provided and they are dimensioned and their pivots 2-8 spaced apart so that when swung into a common plane as shown in FIG. 2, they completely close the opening defined by the frame 27. When swung into parallel relation as shown in FIG. 3, the blades present'a minimum of obstructions or drag to air flow through the opening. To provide for simultaneous swinging through equal angles, the blades are coupled by a linkage 34 effective to swing the blades in opposite directions.

7 The damper .26 is structurally similar to the damper 25 but its frame 31 defines an opening of approximately twice the effective opening of the companion damper. This frame supports the pivot shafts 32 of the damper blades 33. For reasons of economy, the blades 33 are preferably the same size as the blades29 and accordingly the damper 26 requires twice as many blades as the damper 25 in order to effectively control air flow through the opening with which it is associated. These blades are likewise coupled by linkages 39 cifective to swing alternate blades in opposite directions.

To enable the damper mechanism to function in accordance with the requirements of the air conditioning method above described, the dampers 25 and 26 are coupled for simultaneous operation in a manner such that their ilow control actions are complementary. More specifically, the coupling is such that as either damper is actuated toward a closed position the other is opened an equal amount. This requirement compensates for the difference in sizes of the dampers and such compensation is automatically effected by the linkage.

In its prefcrre'd'form the damper coupling linkage comprises an elongated rigid link'SS pivotally connected at one end to a crank arm 36 rigidly fixed to the pivot shaft 32 of one of the cold air damper blades. At its other end the link 35 is pivotally connected to an arm 37 rigidly fixed to the pivot shaft 23 or" one of the blades 29 of the hot air damper. To compensate for the difierence in damper sizes, the arm 35 is made proportionately longer than the arm 37. In the exemplary damper the arm 36 is constructed with a length L twice the length of that of the arm 37 as indicated at L. By reason of this difference in arm length, the blades 33 of the'damper 26 are rocked through an angle approximately half the angle of movementof the blades 29, or, in other words, blades 33 moves through an angle of 45 as the blades 25" move through an angle of 9G". 7

In practice, the linkage is initially adjusted so that movement of the blades 29 of the damper 2S to fully closed position as shown inFIG. 2 results in the movement of the blades 33 of the damper 26 to the fully open position. By dimensioning the effective area of the damper 26 to accommodate the maximum volume of air moved by the blower it), the system may thus be conditioned to supply cold air only to the mixing chamber 13. Conversely, when the damper blades 29 of the damper 25 are swung to fully open position the blades 33 of the companion cold air damper are'swung to a position to cut down the flow through that damper by approximately one-half or an amount corresponding to that passing through the damper 25 so that the total volume of air delivered to the mixing chamber 18 remains substantially constant.

It will be apparent that the proportions of hot and cold air may be varied progressively by setting the dampers in positions intermediate those described. Where temperature conditions are relatively stable, such setting may be elfected manually. Alternatively, a power driven actuator or motor 4% may be provided for setting the dampers under control of a thermostat positioned to sense the temperature after the air is thoroughly mixed in the mixing chamber 18.

Due to the arrangement for turning the damper blades in opposite directions as above discussed, the air is dis charged into the mixing chamber 18 in a manner which insures thorough mixing of the hot and cold air. '.The mixed air may then be delivered to the air outlets of the rooms or other space to be conditioned by way of a duct or ducts 41.

It will be apparent from the foregoing that the invention provides a method by which air can be conditioned very economically. The method is also advantageous in that the apparatus required is relatively simple and thus of low initial cost. More particularly, the improved method permits operation of both cooling and heating apparatus levels which afford maximum economies both with respect to equipment and operating costs.

The invention also provides apparatus of a novel and advantageous character for carrying out the improved air conditioning method in an eiiicient and economical manner. The apparatusis simple in construction and requires a minimum of power for its operation. This is due in a large measure to the damper mechanism and its novel relationship to the other elements of the system which is particularly effective in providing economical operation of the system.

I claim as my invention:

1. Apparatus for conditioning air comprising, in combination, means defining a cooling chamber and a mixing chamber, a pair of passages connecting said chambers, one of said passages having an effective area within the limits of 20% and 60% of the effective area of the other passage, means for moving a constant volume of air through said cooling chamber and said passages to said mixing chamber, a cooler in said cooling chamber operative to cool the air to a predetermined moderately low temperature, a heater in said one of said passages operative to heat the air flowing therethrough to a relatively high temperature, said mixing chamber being efiective to thoroughly mix the hot and cold air delivered through the respective passages, and damper mechanism operatively associated with said passages adjustable to complementally vary the proportion of air flowing through the respective passages while maintaining the total volume of air flowing substantially constant throughout the entire range of adjustment of said damper mechanism to bring the mixture of air in said mixing chamber to a predetermined temperature, said damper mechanism being proportioned to permit complete closure of said one passage while closure of the other passage is restricted to a degree which reduces its effective area to substantially that of said one passa e when the latter is fully open.

2. Apparatus for conditioning air comprising, in combination, means defining a cooling chamber and a mixing chamber, a pair of passages connecting said chambers, one of said passages having an effective area within the limits of 20% and 60% of the etfective area of the other passage, means for moving a constant volume of air through said cooling chamber and said passages to said mixing chamber, a cooler in said cooling chamber operative to cool the air to a predetermined moderately low temperature, a heater in said one of said passages operative to heat the air flowing therethrough to a relatively high temperature, said mixing chamber being effective to thoroughly mix the hot and cold air delivered through the respective passages, a damper operatively associated with each passage, and a linkage connecting said dampers for simultaneous operation so as to complementally vary the proportion of air flowing through the respective passages while maintaining the total volume of air flowing substantially constant throughout the entire range of adjustment of said damper mechanism, said dampers being dimensioned and said linkage being connected therewith so as to permit complete closure of said one passage while closure of the other passage is restricted to a degree which reduces its eifective area to substantially that of said one passage when the latter is fully open.

3. Apparatus for conditioning air comprising, in combination, means defining a cooling chamber and a mixing chamber, a pair of passages connecting said chambers, one of said passages having an efiective area within the limits of 20% and 60% of the effective area of the other passage, means for moving a constant volume of air through said cooling chamber and said passages to said mixing chamber, a cooler in said cooling chamber operative to cool the air to a predetermined moderately low temperature, a heater in said one of said passages operative to heat the air flowing therethrough to a relatively high temperature, said mixing chamber being effective to thoroughly mix the hot and cold air delivered through the respective passages, a damper operatively associated with each passage, the damper for the hot air passage having a maximum etiective area of approximately one-half the eitective area of the damper for the cold air passage, and a linkage connecting said dampers for simultaneous operation so as to vary the efiective areas of the respective areas in a manner which maintains the sum of the areas substantially constant, said dampers being dimensioned and said linkage being connected therewith so as to permit complete closure of said one passage while closure of the other passage is restricted to a degree which reduces its effective area to substantially that of said one passage when the latter is fully open.

4. In an air conditioning system, means defining a pair of passages, one of said passages having an efiective area Within the limits of 20% and 60% to the effective area of the other passage, a blower operative to move a constant volume of air through said passages, a heater in said one of the passages, a damper located adjacent the outlet of each passage, the damper for said heater passage having an elfective area substantiahy smaller than the damper for the other passa e, and a linkage connecting said dampers for simultaneous operation to change the effective area of said smaller damper at a greater rate than the efiective area of said damper for the other passage such .that their combined effective areas remain substantially constant for all damper positions, said dampers being dimensioned and said linkage being connected therewith so as to permit complete closure of said one passage While closure of the other passage is restricted to a degree which reduces its effective area to substantially that of said one passage when the latter is fully open.

5. Apparatus for conditioning air comprising, in combination, means defining an air chamber having an inlet and an outlet divided into two parallel passages, a blower for mov ng a stream of air through said chamber from said inlet to said outlet, air cooling means adjacent said inlet operative to cool the air to a predetermined moderately low temperature, one of said passages having an effective area within the limits of 20% and 60% of the efiective area of the other passage, a heater in said one passage adapted to be maintained at a constant relatively high temperature, a damper positioned adjacent the outlet of each passage effective to control air flow therethrough, and a linkage connecting said dampers operative to close one damper as the other opens and at a rate such that the combined air flow through the passages remains substantially constant for all damper positions whereby the ratio heated and cooled air may be regulated to produce a predetermined air temperature When the hot and cold air streams are combined and mixed, said dampers being dimensioned and said linkage being connected therewith so as to permit complete closure of said one passage while closure of the other passage is restricted to a degree which reduces its effective area to substantially that of said one passage When the latter is fully open.

References Cited in the file of this patent UNITED STATES PATENTS 2,072,166 Goodman Mar. 2, 1937 2,254,185 Newton Aug. 26, 1941 2,266,029 Haines Dec. 16, 1941 2,702,456 Rinqquist et a1. Feb. 22, 1955 2,806,675 Conradi Sept. 17, 1957 2,971,450 Millman Feb. 14, 1961 

1. APPARATUS FOR CONDITIONING AIR COMPRISING, IN COMBINATION, MEANS DEFINING A COOLING CHAMBER AND A MIXING CHAMBER, A PAIR OF PASSAGES CONNECTING SAID CHAMBERS, ONE OF SAID PASSAGES HAVING AN EFFECTIVE AREA WITHIN THE LIMITS OF 20% AND 60% OF THE EFFECTIVE AREA OF THE OTHER PASSAGE, MEANS FOR MOVING A CONSTANT VOLUME OF AIR THROUGH SAID COOLING CHAMBER AND SAID PASSAGES TO SAID MIXING CHAMBER, A COOLER IN SAID COOLING CHAMBER OPERATIVE TO COOL THE AIR TO A PREDETERMINED MODERATELY LOW HIGH TEMPERATURE, SAID MIXING CHAMBER BEING EFFECTIVE TO THOROUGHLY MIX THE HOT AND COLD AIR DELIVERED THROUGH THE RESPECTIVE PASSAGES, AND DAMPER MECHANISM OPERATIVELY ASSOCIATED WITH SAID PASSAGES ADJUSTABLE TO COMPLEMENTALLY VARY THE PROPORTION OF AIR FLOWING THROUGH THE RESPECTIVE PASSAGES WHILE MAINTAINING THE TOTAL VOLUME OF AIR FLOWING SUBSTANTIALLY CONSTANT THROUGHOUT THE ENTIRE RANGE OF ADJUSTMENT OF SAID DAMPER MECHANISM TO BRING THE MIXTURE OF AIR IN SAID MIXING CHAMBER TO A PREDETERMINED TEMPERATURE, SAID DAMPER MECHANISM BEING PROPORTIONED TO PERMIT COMPLETE CLOSURE OF SAID ONE PASSAGE WHILE CLOSURE OF THE OTHER PASSAGE IS RESTRICTED TO A DEGREE WHICH REDUCES ITS EFFECTIVE AREA TO SUBSTANTIALLY THAT OF SAID ONE PASSAGE WHEN THE LATTER IS FULLY OPEN. 